1. Field of the Invention
The present invention relates to a fuel injuector device for injecting atomized fuel into each cylinder of an internal combustion engine. The present invention also is concerned with a method of producing such a fuel injector device.
2. Description of the Related Art
A known fuel injector device of the type shown, for example, in Japanese Unexamined Utility Model Publication No. 61-152765 is adapted to be used on an internal combustion engine in which each cylinder has two intake valves and an intake passage which is branched into two branch passage portions at a region near the intake valves. Thus, the fuel injector device associated with each cylinder has a single injection nozzle orifice for metering fuel and a fuel passage which is divided into two branch fuel passages disposed immediately downstream of the injection nozzle orifice, the branch fuel passages being inclined with respect to the injector axis so as to distribute the fuel to both intake valves of the cylinder. The axes of the branch fuel passages cross each other at a point upstream of the position where the walls of both branch fuel passages merge each other. It is necessary that the merging walls of two branch fuel passages form a keen edge so a to stabilize the angle of fuel injection and distribution of fuel to both branch fuel passages.
This known fuel injector device has the following problem. Namely, when the fuel is injected and atomized from the single injection nozzle orifice, the central portion of the atomized fuel collides with the fuel passage walls in the region where the passage branches. The particles of the atomized fuel deflected by the passage walls are joined with atomized fuel particles which have been injected into the branch fuel passages without being interfered by the passage walls, thereby to form fuel particles of greater sizes, thus adversely affecting fine atomization.
In addition, the precisions of the fuel distribution and fuel injection angle are adversely affected even by a slight error in the position (angle) and shape of the branching portion of the fuel passage.